Molecular Identification of Free-Living Amoebae (Naegleria spp., Acanthamoeba spp. and Vermamoeba spp.) Isolated from Unimproved Hot Springs, Guilan Province, Northern Iran

This study was conducted to determine the presence and molecular identify of Acanthamoeba, Naegleria and Vermamoeba in unimproved hot springs.

From Jul to Aug 2017, 54 water samples were collected from hot springs in different parts of the Guilan Province, North Iran. For the isolation of Acanthamoeba, Naegleria and Vermamoeba approximately 500 ml of the water samples were filtered through a cellulose nitrate membrane with a pore size of 0.45 μm. The filter was transferred onto non-nutrient agar plates seeded with Gram-negative bacteria (Escherichia coli) as a food source. The morphological key of page was used to identify free‐living amoebae (FLA) using an inverted microscope, PCR amplification targeting specific genes for each genus and sequencing determined frequent species and genotypes base on NCBI database.

Fifteen of the 54 samples were positive by culture and/or PCR for Acanthamoeba and other FLA from unimproved hot springs. By sequencing the positive isolates, the strains were shown to belong to Acanthamoeba castellanii (12 case isolates belonged to T4 genotype), 4 cases of V. vermiformis, and 3 cases of N. australiensis, 2 cases of N. pagei and 1 cases of N. gruberi.

Although FLA-mediated illnesses are not as high as in environmental distribution, but because of a poor prognosis, more investigations about FLA distribution in hot springs is critical. Hot spring may enhance exposure of the amoebae in individuals. Hence, more attention to unimproved hot springs is needed to prevent free-living amoebae mediated diseases.